forked from Qortal/Brooklyn
You can not select more than 25 topics
Topics must start with a letter or number, can include dashes ('-') and can be up to 35 characters long.
449 lines
12 KiB
449 lines
12 KiB
// SPDX-License-Identifier: GPL-2.0-or-later |
|
/* |
|
* Copyright (c) 2004 Evgeniy Polyakov <[email protected]> |
|
*/ |
|
|
|
#include <asm/io.h> |
|
|
|
#include <linux/delay.h> |
|
#include <linux/moduleparam.h> |
|
#include <linux/module.h> |
|
|
|
#include "w1_internal.h" |
|
|
|
static int w1_delay_parm = 1; |
|
module_param_named(delay_coef, w1_delay_parm, int, 0); |
|
|
|
static int w1_disable_irqs = 0; |
|
module_param_named(disable_irqs, w1_disable_irqs, int, 0); |
|
|
|
static u8 w1_crc8_table[] = { |
|
0, 94, 188, 226, 97, 63, 221, 131, 194, 156, 126, 32, 163, 253, 31, 65, |
|
157, 195, 33, 127, 252, 162, 64, 30, 95, 1, 227, 189, 62, 96, 130, 220, |
|
35, 125, 159, 193, 66, 28, 254, 160, 225, 191, 93, 3, 128, 222, 60, 98, |
|
190, 224, 2, 92, 223, 129, 99, 61, 124, 34, 192, 158, 29, 67, 161, 255, |
|
70, 24, 250, 164, 39, 121, 155, 197, 132, 218, 56, 102, 229, 187, 89, 7, |
|
219, 133, 103, 57, 186, 228, 6, 88, 25, 71, 165, 251, 120, 38, 196, 154, |
|
101, 59, 217, 135, 4, 90, 184, 230, 167, 249, 27, 69, 198, 152, 122, 36, |
|
248, 166, 68, 26, 153, 199, 37, 123, 58, 100, 134, 216, 91, 5, 231, 185, |
|
140, 210, 48, 110, 237, 179, 81, 15, 78, 16, 242, 172, 47, 113, 147, 205, |
|
17, 79, 173, 243, 112, 46, 204, 146, 211, 141, 111, 49, 178, 236, 14, 80, |
|
175, 241, 19, 77, 206, 144, 114, 44, 109, 51, 209, 143, 12, 82, 176, 238, |
|
50, 108, 142, 208, 83, 13, 239, 177, 240, 174, 76, 18, 145, 207, 45, 115, |
|
202, 148, 118, 40, 171, 245, 23, 73, 8, 86, 180, 234, 105, 55, 213, 139, |
|
87, 9, 235, 181, 54, 104, 138, 212, 149, 203, 41, 119, 244, 170, 72, 22, |
|
233, 183, 85, 11, 136, 214, 52, 106, 43, 117, 151, 201, 74, 20, 246, 168, |
|
116, 42, 200, 150, 21, 75, 169, 247, 182, 232, 10, 84, 215, 137, 107, 53 |
|
}; |
|
|
|
static void w1_delay(unsigned long tm) |
|
{ |
|
udelay(tm * w1_delay_parm); |
|
} |
|
|
|
static void w1_write_bit(struct w1_master *dev, int bit); |
|
static u8 w1_read_bit(struct w1_master *dev); |
|
|
|
/** |
|
* w1_touch_bit() - Generates a write-0 or write-1 cycle and samples the level. |
|
* @dev: the master device |
|
* @bit: 0 - write a 0, 1 - write a 0 read the level |
|
*/ |
|
u8 w1_touch_bit(struct w1_master *dev, int bit) |
|
{ |
|
if (dev->bus_master->touch_bit) |
|
return dev->bus_master->touch_bit(dev->bus_master->data, bit); |
|
else if (bit) |
|
return w1_read_bit(dev); |
|
else { |
|
w1_write_bit(dev, 0); |
|
return 0; |
|
} |
|
} |
|
EXPORT_SYMBOL_GPL(w1_touch_bit); |
|
|
|
/** |
|
* w1_write_bit() - Generates a write-0 or write-1 cycle. |
|
* @dev: the master device |
|
* @bit: bit to write |
|
* |
|
* Only call if dev->bus_master->touch_bit is NULL |
|
*/ |
|
static void w1_write_bit(struct w1_master *dev, int bit) |
|
{ |
|
unsigned long flags = 0; |
|
|
|
if(w1_disable_irqs) local_irq_save(flags); |
|
|
|
if (bit) { |
|
dev->bus_master->write_bit(dev->bus_master->data, 0); |
|
w1_delay(6); |
|
dev->bus_master->write_bit(dev->bus_master->data, 1); |
|
w1_delay(64); |
|
} else { |
|
dev->bus_master->write_bit(dev->bus_master->data, 0); |
|
w1_delay(60); |
|
dev->bus_master->write_bit(dev->bus_master->data, 1); |
|
w1_delay(10); |
|
} |
|
|
|
if(w1_disable_irqs) local_irq_restore(flags); |
|
} |
|
|
|
/** |
|
* w1_pre_write() - pre-write operations |
|
* @dev: the master device |
|
* |
|
* Pre-write operation, currently only supporting strong pullups. |
|
* Program the hardware for a strong pullup, if one has been requested and |
|
* the hardware supports it. |
|
*/ |
|
static void w1_pre_write(struct w1_master *dev) |
|
{ |
|
if (dev->pullup_duration && |
|
dev->enable_pullup && dev->bus_master->set_pullup) { |
|
dev->bus_master->set_pullup(dev->bus_master->data, |
|
dev->pullup_duration); |
|
} |
|
} |
|
|
|
/** |
|
* w1_post_write() - post-write options |
|
* @dev: the master device |
|
* |
|
* Post-write operation, currently only supporting strong pullups. |
|
* If a strong pullup was requested, clear it if the hardware supports |
|
* them, or execute the delay otherwise, in either case clear the request. |
|
*/ |
|
static void w1_post_write(struct w1_master *dev) |
|
{ |
|
if (dev->pullup_duration) { |
|
if (dev->enable_pullup && dev->bus_master->set_pullup) |
|
dev->bus_master->set_pullup(dev->bus_master->data, 0); |
|
else |
|
msleep(dev->pullup_duration); |
|
dev->pullup_duration = 0; |
|
} |
|
} |
|
|
|
/** |
|
* w1_write_8() - Writes 8 bits. |
|
* @dev: the master device |
|
* @byte: the byte to write |
|
*/ |
|
void w1_write_8(struct w1_master *dev, u8 byte) |
|
{ |
|
int i; |
|
|
|
if (dev->bus_master->write_byte) { |
|
w1_pre_write(dev); |
|
dev->bus_master->write_byte(dev->bus_master->data, byte); |
|
} |
|
else |
|
for (i = 0; i < 8; ++i) { |
|
if (i == 7) |
|
w1_pre_write(dev); |
|
w1_touch_bit(dev, (byte >> i) & 0x1); |
|
} |
|
w1_post_write(dev); |
|
} |
|
EXPORT_SYMBOL_GPL(w1_write_8); |
|
|
|
|
|
/** |
|
* w1_read_bit() - Generates a write-1 cycle and samples the level. |
|
* @dev: the master device |
|
* |
|
* Only call if dev->bus_master->touch_bit is NULL |
|
*/ |
|
static u8 w1_read_bit(struct w1_master *dev) |
|
{ |
|
int result; |
|
unsigned long flags = 0; |
|
|
|
/* sample timing is critical here */ |
|
local_irq_save(flags); |
|
dev->bus_master->write_bit(dev->bus_master->data, 0); |
|
w1_delay(6); |
|
dev->bus_master->write_bit(dev->bus_master->data, 1); |
|
w1_delay(9); |
|
|
|
result = dev->bus_master->read_bit(dev->bus_master->data); |
|
local_irq_restore(flags); |
|
|
|
w1_delay(55); |
|
|
|
return result & 0x1; |
|
} |
|
|
|
/** |
|
* w1_triplet() - * Does a triplet - used for searching ROM addresses. |
|
* @dev: the master device |
|
* @bdir: the bit to write if both id_bit and comp_bit are 0 |
|
* |
|
* Return bits: |
|
* bit 0 = id_bit |
|
* bit 1 = comp_bit |
|
* bit 2 = dir_taken |
|
* |
|
* If both bits 0 & 1 are set, the search should be restarted. |
|
* |
|
* Return: bit fields - see above |
|
*/ |
|
u8 w1_triplet(struct w1_master *dev, int bdir) |
|
{ |
|
if (dev->bus_master->triplet) |
|
return dev->bus_master->triplet(dev->bus_master->data, bdir); |
|
else { |
|
u8 id_bit = w1_touch_bit(dev, 1); |
|
u8 comp_bit = w1_touch_bit(dev, 1); |
|
u8 retval; |
|
|
|
if (id_bit && comp_bit) |
|
return 0x03; /* error */ |
|
|
|
if (!id_bit && !comp_bit) { |
|
/* Both bits are valid, take the direction given */ |
|
retval = bdir ? 0x04 : 0; |
|
} else { |
|
/* Only one bit is valid, take that direction */ |
|
bdir = id_bit; |
|
retval = id_bit ? 0x05 : 0x02; |
|
} |
|
|
|
if (dev->bus_master->touch_bit) |
|
w1_touch_bit(dev, bdir); |
|
else |
|
w1_write_bit(dev, bdir); |
|
return retval; |
|
} |
|
} |
|
EXPORT_SYMBOL_GPL(w1_triplet); |
|
|
|
/** |
|
* w1_read_8() - Reads 8 bits. |
|
* @dev: the master device |
|
* |
|
* Return: the byte read |
|
*/ |
|
u8 w1_read_8(struct w1_master *dev) |
|
{ |
|
int i; |
|
u8 res = 0; |
|
|
|
if (dev->bus_master->read_byte) |
|
res = dev->bus_master->read_byte(dev->bus_master->data); |
|
else |
|
for (i = 0; i < 8; ++i) |
|
res |= (w1_touch_bit(dev,1) << i); |
|
|
|
return res; |
|
} |
|
EXPORT_SYMBOL_GPL(w1_read_8); |
|
|
|
/** |
|
* w1_write_block() - Writes a series of bytes. |
|
* @dev: the master device |
|
* @buf: pointer to the data to write |
|
* @len: the number of bytes to write |
|
*/ |
|
void w1_write_block(struct w1_master *dev, const u8 *buf, int len) |
|
{ |
|
int i; |
|
|
|
if (dev->bus_master->write_block) { |
|
w1_pre_write(dev); |
|
dev->bus_master->write_block(dev->bus_master->data, buf, len); |
|
} |
|
else |
|
for (i = 0; i < len; ++i) |
|
w1_write_8(dev, buf[i]); /* calls w1_pre_write */ |
|
w1_post_write(dev); |
|
} |
|
EXPORT_SYMBOL_GPL(w1_write_block); |
|
|
|
/** |
|
* w1_touch_block() - Touches a series of bytes. |
|
* @dev: the master device |
|
* @buf: pointer to the data to write |
|
* @len: the number of bytes to write |
|
*/ |
|
void w1_touch_block(struct w1_master *dev, u8 *buf, int len) |
|
{ |
|
int i, j; |
|
u8 tmp; |
|
|
|
for (i = 0; i < len; ++i) { |
|
tmp = 0; |
|
for (j = 0; j < 8; ++j) { |
|
if (j == 7) |
|
w1_pre_write(dev); |
|
tmp |= w1_touch_bit(dev, (buf[i] >> j) & 0x1) << j; |
|
} |
|
|
|
buf[i] = tmp; |
|
} |
|
} |
|
EXPORT_SYMBOL_GPL(w1_touch_block); |
|
|
|
/** |
|
* w1_read_block() - Reads a series of bytes. |
|
* @dev: the master device |
|
* @buf: pointer to the buffer to fill |
|
* @len: the number of bytes to read |
|
* Return: the number of bytes read |
|
*/ |
|
u8 w1_read_block(struct w1_master *dev, u8 *buf, int len) |
|
{ |
|
int i; |
|
u8 ret; |
|
|
|
if (dev->bus_master->read_block) |
|
ret = dev->bus_master->read_block(dev->bus_master->data, buf, len); |
|
else { |
|
for (i = 0; i < len; ++i) |
|
buf[i] = w1_read_8(dev); |
|
ret = len; |
|
} |
|
|
|
return ret; |
|
} |
|
EXPORT_SYMBOL_GPL(w1_read_block); |
|
|
|
/** |
|
* w1_reset_bus() - Issues a reset bus sequence. |
|
* @dev: the master device |
|
* Return: 0=Device present, 1=No device present or error |
|
*/ |
|
int w1_reset_bus(struct w1_master *dev) |
|
{ |
|
int result; |
|
unsigned long flags = 0; |
|
|
|
if(w1_disable_irqs) local_irq_save(flags); |
|
|
|
if (dev->bus_master->reset_bus) |
|
result = dev->bus_master->reset_bus(dev->bus_master->data) & 0x1; |
|
else { |
|
dev->bus_master->write_bit(dev->bus_master->data, 0); |
|
/* minimum 480, max ? us |
|
* be nice and sleep, except 18b20 spec lists 960us maximum, |
|
* so until we can sleep with microsecond accuracy, spin. |
|
* Feel free to come up with some other way to give up the |
|
* cpu for such a short amount of time AND get it back in |
|
* the maximum amount of time. |
|
*/ |
|
w1_delay(500); |
|
dev->bus_master->write_bit(dev->bus_master->data, 1); |
|
w1_delay(70); |
|
|
|
result = dev->bus_master->read_bit(dev->bus_master->data) & 0x1; |
|
/* minimum 70 (above) + 430 = 500 us |
|
* There aren't any timing requirements between a reset and |
|
* the following transactions. Sleeping is safe here. |
|
*/ |
|
/* w1_delay(430); min required time */ |
|
msleep(1); |
|
} |
|
|
|
if(w1_disable_irqs) local_irq_restore(flags); |
|
|
|
return result; |
|
} |
|
EXPORT_SYMBOL_GPL(w1_reset_bus); |
|
|
|
u8 w1_calc_crc8(u8 * data, int len) |
|
{ |
|
u8 crc = 0; |
|
|
|
while (len--) |
|
crc = w1_crc8_table[crc ^ *data++]; |
|
|
|
return crc; |
|
} |
|
EXPORT_SYMBOL_GPL(w1_calc_crc8); |
|
|
|
void w1_search_devices(struct w1_master *dev, u8 search_type, w1_slave_found_callback cb) |
|
{ |
|
dev->attempts++; |
|
if (dev->bus_master->search) |
|
dev->bus_master->search(dev->bus_master->data, dev, |
|
search_type, cb); |
|
else |
|
w1_search(dev, search_type, cb); |
|
} |
|
|
|
/** |
|
* w1_reset_select_slave() - reset and select a slave |
|
* @sl: the slave to select |
|
* |
|
* Resets the bus and then selects the slave by sending either a skip rom |
|
* or a rom match. A skip rom is issued if there is only one device |
|
* registered on the bus. |
|
* The w1 master lock must be held. |
|
* |
|
* Return: 0=success, anything else=error |
|
*/ |
|
int w1_reset_select_slave(struct w1_slave *sl) |
|
{ |
|
if (w1_reset_bus(sl->master)) |
|
return -1; |
|
|
|
if (sl->master->slave_count == 1) |
|
w1_write_8(sl->master, W1_SKIP_ROM); |
|
else { |
|
u8 match[9] = {W1_MATCH_ROM, }; |
|
u64 rn = le64_to_cpu(*((u64*)&sl->reg_num)); |
|
|
|
memcpy(&match[1], &rn, 8); |
|
w1_write_block(sl->master, match, 9); |
|
} |
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(w1_reset_select_slave); |
|
|
|
/** |
|
* w1_reset_resume_command() - resume instead of another match ROM |
|
* @dev: the master device |
|
* |
|
* When the workflow with a slave amongst many requires several |
|
* successive commands a reset between each, this function is similar |
|
* to doing a reset then a match ROM for the last matched ROM. The |
|
* advantage being that the matched ROM step is skipped in favor of the |
|
* resume command. The slave must support the command of course. |
|
* |
|
* If the bus has only one slave, traditionnaly the match ROM is skipped |
|
* and a "SKIP ROM" is done for efficiency. On multi-slave busses, this |
|
* doesn't work of course, but the resume command is the next best thing. |
|
* |
|
* The w1 master lock must be held. |
|
*/ |
|
int w1_reset_resume_command(struct w1_master *dev) |
|
{ |
|
if (w1_reset_bus(dev)) |
|
return -1; |
|
|
|
w1_write_8(dev, dev->slave_count > 1 ? W1_RESUME_CMD : W1_SKIP_ROM); |
|
return 0; |
|
} |
|
EXPORT_SYMBOL_GPL(w1_reset_resume_command); |
|
|
|
/** |
|
* w1_next_pullup() - register for a strong pullup |
|
* @dev: the master device |
|
* @delay: time in milliseconds |
|
* |
|
* Put out a strong pull-up of the specified duration after the next write |
|
* operation. Not all hardware supports strong pullups. Hardware that |
|
* doesn't support strong pullups will sleep for the given time after the |
|
* write operation without a strong pullup. This is a one shot request for |
|
* the next write, specifying zero will clear a previous request. |
|
* The w1 master lock must be held. |
|
* |
|
* Return: 0=success, anything else=error |
|
*/ |
|
void w1_next_pullup(struct w1_master *dev, int delay) |
|
{ |
|
dev->pullup_duration = delay; |
|
} |
|
EXPORT_SYMBOL_GPL(w1_next_pullup);
|
|
|